The Law And Causes Of Surface Water Resources Variation With The Climate Change In Nile Basin

Water is one of the most important conponents of nature recouses.Since the last century,atmospheric temperature and surface temperature have continuously risen,and also social development has entered an accelerated phase,so natural processes and human activities have caused undeniable influence on water resources.Therefore,it is necessary to study the law of water resources variation and assessment of water.Selecting the Nile River Basin in North Africa as the study area,for the first time,the results of the Nile River Basin water resources subarea are obtained.The historical evolution rules were identified,and the surface water resources in the Nile River Basin were evaluated.The causes of the surface water resources were analyzed from the three factors of climate,underlying surface conditions,and human activities.The details are as follows.(1)Firstly,the thesis summarizes the history,current situation and development trend of water resources assessment,identifies various means and methods for water resources assessment,and selects suitable water resources assessment methods based on the actual situation of the watershed itself.(2)Secondly,the paper carries out basin boundary and the generation and correction of simulated river network for the original terrain of the Nile River Basin,classify the simulated river network.On this basis,the results of the Nile River Basin water resources division were obtained for the first time.In the Nile River Basin,there is one primary sub-region of water resources and a total of 232 secondary sub-regions of water resources,including 37 sub-sectors and 195 sub-sub-basins.There are 1071 three-level water resources divisions.There are altogether 1,805 water resources in four levels.(3)Thirdly,the dissertation discusses the evolution characteristics of the water cycle elements in the Nile River Basin.Different analysis methods are used to study the trend,abrupt change and periodic spatial-temporal distribution of the water cycle elements,and the relationship between precipitation and runoff is analyzed based on the runoff coefficient.(4)Fouthly,the dissertation makes a zoning assessment of the surface water resources in the Nile River Basin.Based on the deep spatial distribution of the average annual runoff and the changes in surface water resources in major river sections,the regional distribution of surface water resources in the Nile River Basin and the spatialtemporal evolution of the Nile River Basin are clarified.(5)Finally,the paper analyzes the causes of the evolution of surface water resources in the Nile River basin from three aspects: climate change,underlying surface conditions,and human activities.It also clarifies the driving role of each factor in the surface water resources of the Nile River Basin and analyzes its impact mechanism.